U.S. Pat. No. 3,930,541 issued to Bowman et al and U.S. patent application Ser. No. 786,737 by E. J. Rozniecki disclose fire suppressant systems for military vehicles. Both systems include hollow metallic panels positioned inboard from the vehicle fuel tank so that enemy projectiles fired into the tank also pass through the hollow panel. Pressurized fire suppressant discharges through the hole formed by the projectile to impact against the fireball generated in the personnel space or engine compartment; the fire suppressant rapidly intermixes with the developing flame to thereby extinguish it before it can explode into holocaust proportions. With this system fireballs have been extinguished in less than 100 milliseconds after passage of the projectile through the panel.
The rapid fire-out time is at the expense of undesired fragmentation of the panel material as the pressurized suppressant enlarges the hole formed by the projectile. The suppressant gas at high pressure (e.g. 900 p.s.i.) attacks the edges of the hole and generates cracks in the surrounding wall material; as the cracks radiate outwardly from the edge of the hole they tend to tear the material away from the panel and into the blast of fast-moving suppressant. If the area inboard from the fire-suppressant panel is a personnel space there is a danger that the flying panel fragments will cause human injury or death.
The present invention provides an anti-fragmentation screen on the inboard face of the hollow panel. The screen has a porous nature that enables the hole to be enlarged by the pressurized suppressant. However the screen walls absorb the force of the torn panel material to prevent the material from fragmenting and blowing into the personnel space.